Electric chain-welding machine.



N0- 783,543. I PATENTED FEB. 28, 1905. A. F. RIETZEL. ELBGTRIG CHAIN WELDING MACHINE.

APPLICATION FILED 0GT.16, 1903.

10 SHEETS-SHEET 1.

W/TNESSES; INVENTOH A TTOHNE Y5 PATENTED FEB. 28. 1905.

A. F. RIETZEL.

' ELECTRIC CHAIN WELDING MACHINE.

APPLICATION FILED OUT. 15, 1903.

10 SHEETS-SHEET 2.

INVENTOH /0 pi 77R?!" 6 A TTOHNE Y5 No. 783,543. PATENTED FEB. 28, 1905. A. P. RIETZEL.

ELECTRIC CHAIN WELDING MACHINE.

APPLICATION FILED OUT. 15, 1903.

10 SHEETS-SHEET 3.

TIQFE INVENTOH I BY ATTORNEYS WITNESSES.

No: 783,543. I PATENTED FEB. 28. 1905, A. BRIE/MEL. ELECTRIC GHAIN WELDING MACHINE.

APPLIQATIC'N FILED OGT.16, 1903.

10 SHEETS-SHEET 4.

WITNESSES. INVENTOH QJOWFRJJ My BY 5 ATTOHNE Y5 No. 783,543. PATENTED FEB. 28, 1905.

A. F. RIETZEL.

ELECTRIC GHAIN WELDING MACHINE.

APPLICATION FILED 001:. 15, 1903.

10 SHBETSSHEET 5.

fi ti T dr l nesses.

PATENTED FEB. 28, 1905. A. F. RIETZBL.

ELECTRIC CHAIN WELDING MACHINE.

APPLICATION FILED 00115, 1903.

10 SHEETS-SHEET 6.

@W M WM MM wM alpumi A My? A TTOBNE Y5 W/TNESSES:

PATENTED FEB. 28, 1905.

A. F. RIETZEL. ELECTRIC CHAIN WELDING MACHINE.

APPLICATION FILED OCT. 16, 1903.

1 EETS-SHEET 7.

INVENTOH mam TREK 6/.

BY WW WITNESSES-i a W PATENTED FEB. 28, 1905.

A. F. RIETZEL.

ELECTRIC CHAIN WELDING MACHINE.

APPLICATION FILED 001215, 1903.

10 SHEETS-SBIEET 8.

WITNESSES. INVENTOH E W fi /o a/f I fiw f c/ PATENTED FEB. 28. 1905.

A. P. RIETZEL.

ELECTRI G CHAIN WELDING MACHINE.

PPLIOATION FILED 001215, 1903.

10 SHEETS HIIET Q INVENTOH 1 76/ WITNESSES.

10 SHEETS-SHEET 10.

PATENTED FEB. 28, 1905.

A. F. RIETZEL.

ELECTRIC CEAIN WELDING MACHINE.

APPLICATION FILED 0UT.16, 1903 #VVENTOH WWW? ATTORNEYS W/TNESSES:

No. 783.543. Patented February 28, 1905.

UNITED STATES PATENT OEEIcE.

ADOLPI-I F. RIETZEL, OF LYNN, MASSACHUSETTS, ASSIGNOR TO THOMSON ELECTRIC WELDING COMPANY, OF LYNN, MASSACHUSETTS, A CORPO- RATION OF MAINE.

ELECTRIC CHAIN-WELDING MACHINE.

SPECIFICATION forming part of Letters Patent No. 783,543, dated February 28, 1905,

Application filed October 15, 1903. Serial N0.1'7'7,140.

whom W/ (On/067%! clamping devices to apply the necessary end Be it known that I, ADoLrH F. RIE'IZEL, a pressure as usual in the art to affect the heated 5 o citizen of the United'States, and a resident of work. Lynn, in the countyof Essex and State of Mas Another part of my'invention relates to an 5 sachusetts, have invented certain new and use improved means for hammering or subjecting ful Improvements in Electric Ohain-lVelding the work to other mechanical forging or shap- Machines, of which the following is a speciliing operation applied thereto after it has been 55 cation. subjected to the heating and to pressure by My invention relates to that class of electric the manipulation of the work-supporting or metal-working apparatus in which the heating work-holding slide or carrier. The main obpower of an electric current is used to reduce ject of this part of my invention is to provide the metal toasemiplasticcondition forthe pura simple and readily-controllable means for 60 pose of permitting the same to be forged, reducing the bur or upset produced in the shaped, welded, or otherwise worked, as well electric butt-welding operation and which understood in the art. shall be capable of being actuated or conhile my invention is primarily designed trolled at will, so that it may be made to act as an improvement in electric welding appato any required extent and, if desired, while 65 ratus, it is in some of its features applicable the welding pressure is maintained. also to machines whose work-holders or other The invention consists also in the special appliances are constructed with special refercombinations of devices for effecting the opence to the use of the machine for other metaleration of the hammer or press and for seworking operations. curing other results, as more particularly here- 70 In the followingspecification I shall describe inafterdescribed. Preferably in electric weldmy invention more particularly as carried out ing the anvil and hamn'ier or press are made in a machine organized for electric welding, with engaging surfaces in the form of dies of and particularly for the operation of welding proper shape to give the desired finish to the endless shapes of metal, like the links of a work. 75

- chain. Another part of my invention relates to the One part of my invention relates to the mechanism or devices for actuating the workform or construction of the work-holder of holder to apply the welding or upsetting presthe machine. Heretofore in this elasscf niasure and (in the special class of machine here chines it has been usual to employ clamping in described) to effect a clamping of the work 0 devices which require to be manipulated prior at the same time. This part of my invention to the operation of the machine, said elampconsists in an improved combination of tog ing devices being mounted upon the workgles and actuating-lever, whereby the workholding slides or carriers. This part of my man may apply a heavy pressure to the work,

invention consists of a work-holder adapted by as hereinafter described. 8 5 the conformation of its work engaging or The invention relates, further, to the means holding surfaces to properly locate the work for applying heating-current to the work by in the machine and to effect a clamping of contact-electrodes brought into engagement the same by the usual pressure applied to the with the same by movement in the lateral (liwork-holding slide for thepurpose of welding rection or transversely to the line of operaor upsetting the work. This part of my intion of the work-holders. The object of this vention is particularly useful for welding the part of my invention is to permit the applica- 45 links of chains or for weldiug other endless tion of a heavy heating-current to the work forms of metal, since all that is necessary is by side contact-electrodes and also to permit to place the piece of work in the holders and an adjustment of said contact-electrodes for then without any' further manipulation of wear as well as for varying the projection of the work, or, in other words, the extent of the heated section or portion of the work, by determining the position or point at which the contact-electrode supplies the heating-current. Broadly stated, this part of my invention consists in the combination, with the work-holders for an electric metal-working apparatus and their operating devices, of lateral contact-electrodes mounted upon suitable slides or carriers which are in connection with a stationary source of heating-currentsuch, for instance, as the secondary of a transformer. This part of my invention has to do, further, with the special construction and manner of mounting the contact-electrodes and their slides or carriers, and also to the general combination and disposition of the transformer and other portions of the apparatus comprising the work-hold ers and their operating mechanism.

A further object of the invention is to equalize or exactly determine the pressure with which the contact-electrodes shall engage the work and also to secure a uniformity of pressure contact when said electrodes are operated by a power which is liable to varyas, for instance, by a treadle operated by the foot of the workman. This part of my invention consists, broadly, in the combination, with a pair of contact-electrodes adapted to engage the work laterally at opposite sides of the heated section, of an equalizing lover or link interposed between said contactelectrodes and the actuating power.

The invention further consists in the interposition of a spring between each or either of said contactelectrodes and the actuating power, as well as in other details of construc tion and combinations of parts.

The invention also relates to the means for actuating the controlling device for the apparatus or mechanism which automatically stops the flow of current through the work when the work-holder has been moved to a predetermined extent. This part of my invention consists, broadly, in the combination, with the work-holder or work-holding slide, of a controlling device connected therewith through motion-multiplying mechanism, so that a comparatively large movement of the controlling device will be produced by a small movement of the work-holder. This part of my invention is particularly useful in machines designed to operate on heavy workas, for instance, heavy chain-links.

The invention relates also to the novel construction of replaceable and reversible hammer-die and in other details of construction and combinations of parts, as more particularly nate certain internal stresses which would exist in and weaken the welded link if it were employed without first drawing out the bur or upset of the weld.

My invention has various other objects and features which can be most readily developed in the course of the following more specific description and which are fully disclosed therein.

The following description and the accompanying drawings, which illustrate it, relate specifically to only one form and construction in which my invention may be embodied; but it will of course be understood that by the application of technical knowledge and mechanical skill my invention in its broadest conception may be diversely modified and may be embodied in numerous structural forms without in any wise departing from or exceeding its present scope or spirit. It will also be apparent to those versed in the art that many of the specific features disclosed are in no wise essential to my invention in its broadest aspect, but may be dispensed with or modified in various of its particular applications and usages and still have an operative embodiment of my invention broadly.

For the purpose of illustrating my invention I have chosen to show and describe the same as embodied in a machine for welding the links of chains; but, as already stated, it is in many of its features applicable to other electric metal-working machines.

In the said drawings, Figure 1 is a plan of the table of a machine embodying my invention and shows part of the electric welding mechanism with a portion of a chain in position for welding one of its links. Part of the bur-removing or link-hammering mechanism is also shown; but the upper portion of that mechanism-that is, the hammer or upper hammer-die and its actuating parts-is removed from the table. Fig. 2 is an elevation of the machine from a viewpoint to the right of Fig. 1. The upper hammer mechanism is also removed from the table in Fig. 2. Fig. 3 is an elevation view looking from the left of Fig. 1 and shows the upper hammer mechanism in position upon the table. Fig. 4 is a front elevation of the entire machine. Fig. 5 is a rear elevation of the entire machine. Fig. 6 is a substantially central sectional clevation of most of the working elements of the machine looking from a position to the right of Fig. 1. The link holding or clamping mechanism and the upper hammer-die mechanism are not shown, and most of the framework is omitted for the sake of clearness. Fig. 7 is a plan of the upper portion of the machine containing a hammer operating mechanism with the clutch-controlling lever by means of which the hammer-operating devices are coupled to the driving power. Fig. 7 shows in perspective the clutch-key that may be used as a part of the clutch mechanism. Fig. 7" is a transverse section through parts, showing the position of the clutch-key when the driving power is rotating freely; and Fig. 7 is a similar section showing the position of the clutch-key and parts when coupled. Fig. 7 illustrates the position of the control-arm and clutch-key when engaged with the clutch-controlling lever to permit the power to rotate freely, and Fig. 7 shows the same parts when the clutch-key arm is released so as to couple the hammer-actuating shaft to the driving power. Fig. 8 is a rear elevation of the transformer and the movable terminals or contact-carriers of its secondary circuit, showing the movable terminals 91 and 92 sectioned on the line a a of Fig. 6 and showing the transformer-core 106 divided on its normal line of division 5 b, Fig. 6. The

primary coil 111 and the current-controlling secondary coil 112 are omitted from this view. Fig. 9 is a detail plan of the right-hand linkholding die or work-holder 5. Fig. 10 is a sectional elevation of the right-hand linkholding die or work-holder 5 looking in front of the die and taken on the center line of the chain as indicated at a (L, Fig. 9. Figs. 11, 12, and 13 are respectively a left-hand ele vation, a rear elevation, and a plan view, of the sliding bracket or die-post for holding the lower hammer-die. Fig. 14 is a side elevation of the lower hammer-die; and Fig. 15 is a sectional end elevation thereof, taken on the line a a of Fig. 14. Fig. 16 is a plan view of one of the upper roller bea-rings proper for the movable terminals or contact-carriers of the secondary circuit. Fig. 17 is a diagram corresponding to a rear elevation and shows a convenient method of feeding the chain through the machine while its links are being welded. 17 also illustrates one operation of a special process of welding a chain characterized by a certain arrangement of previously-weld ed chain-links or stamped on drop-forged weldless links, together with links which are to be welded in the machine, as will be more fully explained hereinafter. Fig. 18 is a plan view and diagram illustrating the method of heating the contiguous ends of the link preparatory to welding and discloses a particular and important feature of the heating process, which depends upon a certain formation of the said contiguous ends. Fig. 19 shows the links after the weld has been made, but before the bur or upset has been drawn out by the hammerdies. Fig. 20 shows the finished link. Fig. 21 shows in side elevation a modification in the form of a nose or engaging portion of the contact which passes current into the link laterally. Fig. 22 is a plan ofa pair of contacts modified as indicated in Fig. 21.

The main frame of the machine comprises the bed-plate 113 and the right and left legs 124 and 125, respectively, mounted upon the bed-plate and supporting the table 114.

The particular form of machine illustrated is designed to weld together the ends of that form of link which is bent up or otherwise formed from a single piece of metal. In Fig. 18 this form of link (designated by 1) is shown in plan view on a comparatively large scale. The juncture which is to be welded is located in one side of the link midway between its ends.

The link or other object which is to be welded or otherwise worked is clamped longitudinally and in a horizontal plane between the left and right holding-dies 4 and 5, respectively, and with its open or broken side being toward the rear of the machine and facing the contact electrodes or contacts 101 and 102, which by making contact with the work supply heatingcurrent thereto. These work-holders or holding-dies are firmly bolted in suitable recesses conforming to their outline in the left and right horizontal dieslides or holding-die slides 26 and 22, respectively, mounted upon the table 114, near the front thereof, and adapted to slide horizontally in right and left directions toward and from each other. The left slide 26 is normally stationary. It is mounted between suitable guides 27 and 28, formed upon the table. It is longitudinally adjusted, and its extreme left-hand position is variably limited by the adjustable stop-screw 29, mounted in a suitable bracket 30 and abutting against the outer end of the slide.

The right horizontal die-slide 22 is mounted between suitable guides, such as 130, formed upon the table, and is held down by front and rear gibs 23 and 24, bolted upon its said guides. This is the movable one'of the horizontal or holding-die slides or work-holders. It is actuated by a double toggle (or toggle-actuated toggle) comprising a secondary toggle, which moves the slide directly, and a primary toggle, which actuates the secondary toggle and which is actuated by a long hand lever or clamping-lever 9.

The outer or fixed toggle-arm 18 of the secondary toggle is pivoted at its outer or extreme right end to the fixed stud 19, inserted in a suitable boss 139, formed on the table. The inner toggle-arm of the secondary toggle comprises a forked or slotted head 17, which receives the swinging end of the fixed togglearm 18 and comprises a slide end 126, screwed into the slotted head and pivoted to the right end of the movable holding-die slide by a stud 21. The fixed arm of the primary toggle is constituted in a block or casting 10, pivoted at one point to the fixed stud 13, inserted in the table, and at another point slotted to receive the rear end of its complementary toggle-arm 15, which is in the form of a simple flat link and is pivotally secured in the said slot by a pin 14 passing through it and the casting 10. The forward end of the arm 15 of the primary toggle is inserted in a slot in the swinging end IIO i which show the right die 5.

of the fixed arm 18 of the secondary toggle, and a pivot-pin 16, passing through said forward end and the cooperating ends of both secondary toggle-arms, serves to pivotally unite the three ends. The casting 10 also constitutes the pivotal head for the hand-lever 9, which is bolted in a suitable recess or slot in the top of the casting. This right-handlimit position of the movable horizontal slide 22 is variably determined by the adjustablestop-screw 20, which is mounted in a suitable lug or bracket 129 and engages the right end of the slide.

The work-holders or holding-dies 4 and 5 are right and left duplicates, and both are therefore clearly illustrated in Figs. 9 and 10,

The dies are provided with shallow link clamping recesses, such as 5, in their upper surfaces and at their adjacent ends. Each of these link-clamping recesses conforms substantially to the plane outline of the end of the link, which it receives in position for welding. The dies are also provided with outer link-holding recesses, such as 5, in their upper surfaces and extending from their outer ends toward the said linkclamping recesses. These outer link-holding recesses are slightly wider than the links which are to be welded and at their inner ends may also conform substantially to the outline of the chain-links. Each holding-die has a counter recess or channel, such as 5 only slightly wider than the thickness of the chain links and deeper than the clamping and holding recesses, which extends the entire length of the die. When the links which are to be welded are already interlinked in a chain, the outer link-holding recesses receive the horizontal links on either side of the link, which is clamped between the dies in position for welding, while the links of the chain which are disposed in a vertical plane are received by the long narrow counterrecesses. By means of this formation of the holding-dies a single movement of the clamping-lever 9, which brings the dies toward each other, not only serves to clamp the chain-link or other work which is to be welded or otherwise operated on (whether it be separate or linked in a chain) firmly between the dies and in their clamping recesses, but also accurately centers and locates the link in such position that its ends which are to be welded will be engaged by respective ones of the contact-electrodes 101 and 102 when the latter are moved forward on their respective contact-carriers 91 and 92, as will be fully explained hereinafter.

It is obvious that the actuating mechanism described is applicable to die or work holders of the usual form and in which the work is clamped by means independent of those employed in forcing one work-holder toward the other when the work between them has been heated to a suitable extent.

The contact-carriers 91 and 92 are supplied with current from any suitable source, the terminals of which are properly constructed to preserve connection with said carriers during the forward movement of the same to bring the contact-electrodes against the work. By preference I employ as a source of current a secondary of a transformer which may be of the type commonly employed in the art and which as shown comprises a copper casting 104:,constituting a conducting-loop whose current-inducing portion 104C passes through the rectangular opening in the rectangular transformer-co re 106, and thereby makes a conducting-loop around the upper leg or side of the core. The plane of the loop or casting constituting the secondary of the transformer is parallel to the line of movement of the workholding slides. Its loop is broken by a narrow gap and is formed with upwardly-projecting rectangular left and right terminal blocks 10 1 and 104", respectively, which extend through a rectangular opening in the table. The rear surfaces of these terminal blocks 104: and 10 1" are flush with the rear surface of the lower portion of the loop; but the forward ends of the blocks extend considerably infront of the lower portion of the loop in order to give the blocks ample length to bear and make contact with their respective contact carriers or slides 91 and 92. These terminal blocks 101 104" are provided with suitable guides or ways adapted to permit contact-carriers to move in a line transverse to the plane of the loop or secondary and so as to bring the contact-electrodes sidewise against the work.

At each of its four corners and immediately beneath the table the casting 10 1 of the secondary circuit is provided with suitable lugs by means of which it is bolted to the under side of the table. The terminal blocks are insulated from each other by an insulating-plate 105, interposed between them, and the entire casting 10 1 is insulated from the table by suitable insulating-plates, bushings, and washers, as indicated.

In each of its opposing faces the seeomlary loop is provided with a loop-shaped slot or recess 104 passing through the core-opening and around the upper leg of the core. front one of these recesses the front coil 110 of the primary circuit is embedded, while the rear recess similarly receives the rear coil 111 of the primary circuit and also the current-controlling secondary coil 112, disposed around the coil 111 and concentric therewith.

The coil 112 generates a current which may be used in the manner set forth in patent to Lemp and Anderson, No. 519,336, dated May 8, 1894, or in any other suitable way in connection with the devices that control the supply of current to the work.

The transformer-core is made in halves 100, separable at the center line b I of the secondary loop-casting. Each half is built up of ,In the ICC laminae bound together between end plates 107 by suitably-insulated bolts. By means of tie-bolts 108 passing through guide-holes in suitable lugs formed on the end plates the two halves of the core are bound together between two pairs of suitably-insulated bindingyokes 109, which horizontally cross the outer ends of the core. The core rests upon an insulating-plate on the bed 113 and is secured in place by insulated bolts passing through lugs horizontally extending from the lower edges of the end plates 107.

The upper surfaces of the terminal blocks 10 i and 104C are provided with broad longitudinal guidechannels in which the lower roller-bearings of the contact-carriers are inserted and run longitudinally. The contactcarriers 91 and 92 are elongated blocks of copper provided on their under side with depending longitudinally-disposed ridges which project into and nicely fit the guide-channels of their respective terminal blocks and bear upon the roller-bearings lying in the channels.

The upper sides of the contact-carriers are provided with longitudinal guide-channels narrower than those of the terminal blocks and in which the upper roller-bearings of the contact-carriers are disposed. Above and uponthese upper roller-bearings are mounted the upper bearing-plates 98. A carrier-stud 95, passing through each end of each of the upper-bearing-plates, is inserted between the rollers of its respective upper roller-bearing through a longitudinal slot (such as 91) in its respective contact-carrier between the rollers of the lower bearing and into its corresponding terminal block, wherein it is firmly fixed. A sheet-metal bearing-spring 97 is slipped over the upper end of each stud and is caused to bear down upon its respective end of its corresponding upper bearing-plate by a nut fitting the upper end of the stud and screwed down upon the spring. By means of this organization each contact-carrier is mounted with roller-bearings between its respective terminal block and upper bearingplate, whereby it may be moved longitudinally with negligible friction. The carrier-studs, their nuts, and the springs serve to hold the entire combination together, and the pressure of contact between the contact-carriers and their roller-bearings may be varied and adjusted by means of the nuts.

The upper and lower roller-bearings proper of the contact-carriers are the same. in general construction and differ only in their overall dimensions and the number of rollers they employ. The arrangement is clearly illustrated in Fig. 16. The rollers 103 are mounted in a frame comprising two side bars 93 of oblong cross-section connected at their ends and middle by round cross-bars 9 1, riveted to the side bars. The rollers are pivotally mounted at either end by pins driven fixedly into the ends of the rollers, butturning freely in bearing-holes in the opposing side bars of the frame. It will be noted that the rollers are widely separated at two points in the hearing in order to clear the carrier-studs 95.

The left and right contact-electrodes 101 and 102 are mounted, respectively, upon the left and right contact-carriers. The contactelectrodes are elongated copper blocks of 01' long cross-section and lie in a horizontal plane in nicelyfitting contact-guiding grooves or channels cut across the upper surfaces of the carriers at an angle to their longitudinal axes and extending from the outer sides of the car riers diagonally forward and inward toward each other and the work holding clamp. \Vithin these grooves the contact-electrodes are slidable convergingly toward each other and at the same time toward the front of the machine and the work, and the movement of each contact-electrode in an angular direction relative to its respective carrier is resolvable into two rectangular components, one of which is a forward-and-backward movement parallel to the movement of the carrier and the other of which is a lateral component or movement toward or from its opposite contact-electrode.

The positions of the contact-electrodes may be nicely varied and determined by the adjustmentscrews 116, which bear upon the rear ends of the contacts and are supported in angularly-disposed depending lugs 99, hanging in the outer ends of the contact-electrode grooves and formed upon the oblong plates 99, which bridge the grooves and are bolted to the edges of the carriers.

The contact-electrodes are firmly clamped in place underneath rectangular clampingplates 99, which clampingplates are also partly inserted in the grooves and are held down by bolts 100 passing through them and through central longitudinal slots in the contacts and screwed into the bottoms of the contact-guiding grooves. The forward or contact end of each contact-electrode terminates in two normal vertical planes, one of which constitutes the contact-surface of the electrode. This surface is parallel with the portion of the link with which it is to make contact and is provided with a slight groove to receive the side of the link and increase the surface of the contact as well as to furnish a ledge or overhang which will prevent the work from rising from its position in the work holders.

Each of the contact-carriers is provided with a stud 88, screwed into its rear end, secured by a lock-nut and projecting horizontall y backward. The rear ends of the studs pass through opposite ends of the pressureequalizing lever or yoke 85 and are provided with yoke-retaining collars 86, pinned to the studs outside the yoke. The studs and their collars are insulated from the yoke by suitable bushings and washers, as indicated.

Equalizing compressionsprings 87 are mounted on the studs and each is interposed between the yoke and a spring-nut 89, screwed upon its respective stud. At their ends adjacent to the yoke the springs bear upon steel washers mounted on their respective studs and insulated from the yoke by insulating-washers interposed between the yoke and the said steel washers.

The contact-carriers are actuated by a foottreadle or other means, forcing the equalizing yoke or lever toward the contact-carriers by a power supplied at the middle portion of the yoke. The foot end of the treadle projects in front of the machine near the floor, and the rear end is pivotally mounted upon a suit-able shaft 76, which may be secured in a floor-bracket. (Not shown in the drawings.) The lower end of the vertical pull-rod T7 is pivoted between two upwardly projecting lugs, such as 140, formed upon the foottreadle. The upper end of the pull-rod is inserted and pivoted in a slot in the end of the forwardly-extending horizontal arm 78 of the carrier-actuating bell-crank 7 8. The upper or vertical arm 78 of the bell-crank is of circular or curved outline, is slotted, and is interposed between the rear face of the equalizing-yoke and a washer placed under the head of the yoke-bolt 8 L, which passes through the slot and is screwed into the center of the yoke. The bell-crank is pivoted upon a pin 79 between two upwardly-extending lugs formed on the bell-crank bracket 80, secured to the table. This bracket is also provided with upper and lower guide-lugs 80 and 80", in which the vertical spring-plunger 81 is mounted. The carrier-retraction spring is a compression-spring 83, coiled upon the springplunger and interposed between the lower lug 80 and a spring-collar 82, fixed upon the plunger, whereby the plunger is forced upward against the horizontal arm of the bell-crank, upon which the upper end of the plunger presses. This spring-pressure restores the bell-crank and retracts the carriers and their contact-electrodes after removal of the footpressure upon the treadle,which has brought the contact-electrodes into contact with the chain-link or other work. A stop-finger 79, formed on the bell-crank, engages the bellcrank bracket and limits the retractive movement of the parts.

The double-ended lower hammer-die or anvil 7 is a fiat oblong piece of hardened steel mounted with its working end underneath the clamping position of the link to be welded or other work and having its opposite or clamping end extending forward, the longitudinal axis of the die being disposed in a horizontal plane and at right angles to the center line of the chain-link and the flat sides of the die being vertical. The die is mounted in the holding-slot 8 in the top of the vertical die-post 8. The outer or clamping portion 8 of the top of the die-post is higher than the rear or inner portion, so that while the inner or working part of the die is inserted in a shallow slot which engages its sides only part way up the outer or clamping portion of the die is embedded in a deeper slot, the sides of which rise almost as high as the top of the die. The clamping-plate 118, which conforms in plane outline to the raised portion 8 of the die-post, lies on top of the die and is provided with a bearing-ridge 118 running along the left edge of its under side and bearing on the die-post.

A clamping-stud 119, inserted in the diepost on the left of its die-holdii'ig slot, projects up through the clam ping-plate at a point between its bearing-ridge and the die, and a pair of nuts screwed over the clamping-stud and down upon the clamping-plate serve to hold the plate down upon the die and firmly clamp the latter in the die-holding slot in the die-post. Angular displacement of the clamping-plate is prevented by a pin 8, inserted in the top of the die-post and projecting upward through the plate and on the side of the slot opposite the 'clanniing-stud. Longitudinal displacement of the die is prevented by a dowelpin 8", inserted in the bottom of the die-holding slot and projecting upward into a central hole in the die.

The die is formed with interchangeable ends, so that when its working end becomes worn away or softened by contact with the heated chain-link, so as to be no longer fit for forming the link, the die may be turned around and its clamping fend substituted for its working end. To effect this purpose, the top of the die is provided at either end with a semicircular bur-redueing or link-finishing die-recess 7 and a semicircular clearance-recess 7". Either end of the die is also provided with two opposite rectangular clearance-recesses 7" in its opposite sides and underneath the semicircular clearance-recesses 7". These rectangular recesses are designed to give clearance, with the holding or clamping dies 4: and 5 on either side of the lower hammer-die, when the latter is raised by its die-post so as to come between them and into operative contact with the welded chain-link. When the lower hammer-die is thus raised, the die-recess in its working end engages or receives the lower side of the welded half of the chain-link immediately at the point of weld where the undesirable bur has been formed, while the adjacent semicircular recess 7" gives ample clearance between the lower hammer and the opposite half of the chain-link. it will of course be obvious that, if desired, the lower half of the lower hammer-die may be provided with recesses corresponding to those in its upper portion, the die being made symmetrical with respect to its longitudinal axis as well as rela- Thus the die may tive to its transverse axis.

be provided with four link-forming recesses, all of which may be available before the die is discarded or retempered.

The opposite forming-die 6, mounted directly above and coacting with the lower or supporting die 7, may be of any desired type 7 and actuated and controlled in any desired manner. Preferably this opposite die is a hammer-die actuated by any suitable driving power and called into operation by a suitable controlling mechanism, such as a clutch, and of such character as to deliver one or more blows for each operation of the controlling device. The particular mechanism shown is of the character of the trip device which lifts the hammer or tool against a spring and then releases the same. These parts are mounted in a suitable frame comprising two substantiall y vertical and parallel webs 120, terminating in legs below and united above by two cross-bars 1 11 and 142, the former above the latter.

The upper hammer-die proper, 6, is fixedly secured to the lower end of the verticallyreciprocating die-shaft 69 by means of the knurled clamping-collar 74:. The die-shaft is mounted in suitable upper and lower bearings upon the upper and lower cross-bars of the frame'and is maintained in fixed angular position by any suitable guiding device.

The hammer or die 6 is a piece of round hardened steel flattened on either side and preferably provided with a bur-removing or link-finishing die-recess in its lower end. The die-shaft is so centered that in its lowest position the die-recess engages and fits around that portion of the chain-link which has been welded and upon which the welding-bur exists.

A stop-shoulder is provided on the shaft above the lower bearing, as shown at 71, so as to engage the bearing and limit the downward stroke of the shaft and its die in case they drop, through any inadvertence, before the chain-link and lower hammer-die are in proper positions to receive the impact.

As a means for operating the hammer and controlling its action the devices to be now described may be employed and so organized that when coupled to a suit-able actuating power. the hammer will automatically deliver one or more blows and then the power will antomatically uncouple itself. While I prefer to employ a hammer and actuating mechanism ofthis character, so that by the simple movement of the controlling-lever the hammer may be caused to'deliver one or more blows. I do not claim such mechanism as my invention; nor do I desire to limit myself to the employment of a clutch for controlling the application of power to the hammer, since, as will be obvious, other operating powers and other controlling devices might be employed. In the particular form of apparatus shown the vertical reciprocating shaft carrying the up per die 6 is provided with a raising shoulder or projection 62, as shown in the dotted lines,

A fly-wheel 122, driven by a belt in the left I hand direction, (looking at the left of the machine) normally runs freely on the left end of the cam-shaft 59. It may be locked to the cam-shaft 59 at will by means of a clutch controlled by the horizontally-disposed elbow-le ver 63, pivotally mounted upon a stud or projection 61 on the outside of the left frame-web 120. The function of the clutch in the organization claimed by me is simply to control the operation of the hammer by throwing into action the power which operates the same, and said clutch is to be taken as typical of any powercontrolling device whose nature or character would of course vary with the power employed. It is also to be understood that while I have described the use of an upper forming-die which acts by impact I do not limit myself to the manner of actuating said die, since it is obvious that it might be, as well understood in the art, so operated as to apply pressure instead of impact.

The particular form of clutch device herein shown comprises a clutch-key 123. (Shown in detail in Fig. 7.) This key is of cylindrical form at its opposite ends to adapt it to be mounted and to turn freely in bearings formed, respectively, in a collar 121, keyed or suitably secured to rotate with the camshaft 59 in the head or cap 121 on the outer end of said shaft. The intermediate portion of said key is cut away, as shown, and such cut-away portion is located in the hub 122 of the wheel 122. In the inside of the hub next the shaft 59 is a key-groove 55, in which the key is adapted to turn. When the clutch-key stands in the position shown in Fig. 7", which is a cross-section through the fly-wheel hub and shaft 59, it is obvious that the wheel and hub 122 may run loose, but that by turning the clutch-key, so as to bring it into position shown in Fig. 7, said wheel and hub will be locked to the shaft 59, and the latter will be rotated by the power applied to the wheel 122. The clutch-key 123 is provided with a controlling-arm 123*, against the inside of which presses a sprin 56, confined between said arm and the pin 5, secured to the inside of the hub or collar 121. Said spring tends to turn the clutch-pin into the position shown in Fig. 7 which is the position in which the parts will be coupled, as shown in Fig. 7. The clutch is normally held in position as shown in Fig. 7 which is the position in which the parts are uncoupled, as shown in Fig. 7 by the engagement of said arm with the toe or projecting arm of the clutch-control lever 63 when in position shown in Fig. 7 and Fig. 7". This position of the parts is maintained by the friction between the rotating and stationary members of the clutch, "Vhen the clutchcontrol arm 63 is turned to one side to free the arm 123 of the clutch-key. said clutchkey turns to the position shown in Fig. 7 as soon as the key-groove 55 in the hub of the rotating member comes around to coincidence with the clutch-key, and the parts become locked, so as to turn together in the relation shown in Fig. 7", and because the spring 56 turns the clutch-key in its bearings.

So long as the clutch-control lever remains turned to one side to be out of the path of the clutch-key arm the cam-shaft 59 will rotate and operate the hammer in the usual manner; but when the clutch-control lever 63 is permitted to turn back to the position shown in Fig. 7 the clutch-arm by engaging said lever will turn the clutch-key to position shown in Figs. 7 and 7, so as to uncouple the driving power.

It is obvious that in the place of the form of clutch device just described any other form may be used which will effect the same operation.

The bur-reducing or link-finishing operations of both the upper and lower hammerdies are controlled by a single hand-operated lever 31, which may he therefore designated as the finishing-lever. It is a long lever pivoted at one end by a stud 4:1 to a bracket secured to the rear of the left leg 125 of the frame. The lever extends forward across the left side of the machine and to a distance considerably in front thereof, where it is furnished with a suitable handle. A simple vertical link 33 is pivoted at its upper end to the finishing-lever by a pin 32 near its handle. The lower end of this link is pivoted in a slot in the swinging end of the rocker-arm 35, Exedly mounted on the outer or left-hand end of the rock-shaft 36, whose inner end is mounted in the vertical walls of the guide-bracket 136 of thelower hammer-die slide 38. This bracket is mounted upon the bed, and between its said walls the cam 37 is fixedly mounted on the rock-shaft.

Above the rocker-cam 37 and resting upon it is the lower hammer-die slide 38, provided with vertical guide-ribs 38, projecting from its opposite sides and sliding in suitable guidegrooves in the opposing vertical walls of the slide-bracket. The slide is held in place by gibs 1&3 overlapping its guide-ribs and bolted to respective walls of the bracket. Upon the upper end of the slide the die-post 8 of the lower hammer-die is mounted and secured by a bolt. A spring-lug 38" projects rearward from the lower end of the slide and rigidly supports the lower end of the vertical springstud 39, the upper end of which passes freely through a hole in a spring-lug 136, formed on the guide-bracket. A compression-spring 4C0, coiled around the spring-stud and interposed between the spring-lugs, forces the slide always down upon the rocker-cam.

The rocker-cam 37 is provided with radiallyextending stop portions 37 and 37, which engage a common stop-pin located between them and mounted in the vertical walls of the guidebracket. The angular movements of the rocker-cam, its rock-shaft, and the finishinglever 31, connected therewith, are thereby limited.

To operate the power controlling device,

such as the clutch already described or any other device having a similar function, as already set forth, the following devices connected with the finishing-lever or other means which operate the cam 37 or device for lifting the lower die may be employed. Preferably these devices embody a trip pawl or dog of such nature that it will engage or look in one movement of the parts, but will move freely in the opposite movement of the parts. An upwardly-projectin g pawl-bracket 42, secured on the outside of the finishing-lever 31 near its rear or pivoted end, carries atits upper end a pawl 46, mounted on a stud 43, inserted in the inner face of the bracket. The pawl has a pa wltooth 4:6projecting radially fromj ts u pperside and a radial stop projection L6 projecting from its lower side and engaging the stop-screw 45, inserted in the pawl-bracket below the pawl. The pawl has a short hub or boss lying against the pawl-bracket. A circular wire spring M is coiled around this boss and has one end anchored to the stop-pin L5, while its other end is inserted in the stop projection 46" and tends always to turn the pawl, so as to bring the stop projection against the stop-pin. Immediately above the pawl a trip-collar 4:7 is fixed upon the outer end of the horizontal rockshaft 48, mounted in a suitable bracket 135, bolted on the table. The trip-collar is provided with a radially-depending trip-tooth 47 in position to make engagement with the pawltooth s6 of the pawl when the latter passes through its arc of motion about the finishinglever pivot 41 as an axis. Upon the end of the rock-shaft 4:8, opposite the trip-collar, is fixed a horizontal rearwardly -extending rocker-arm 49, slotted at its swinging end. A vertical connecting-link 51, including an adjustable turnbuckle, has its lower end pivoted in the slot in the rocker-arm L9 and its upper end pivoted in a similar slot in the horizontal arm of an elbow-lever 53, whose ver tical arm connects by a link with the clutchcontrolling lever '3, which elbow-lever is provided with a retractable spring 57, as shown in Fig. 3.

During a first part of the angular movement of the finishing-lever its slide-raising portion of the finishing-levers downward movement,

and hence after the lower or supporting hammer-die has been brought into operative engagement with the chain-link to be finished, the pawl-tooth on the pawl 43 engages the trip-tooth on the trip-collar 47 and forcibly turns the latter and its rock-shaft 48 so as to depress the swinging end of the rocker-arm 49, pull down on the link 51, and through the intermediate devices turn the clutch-control lever 63, thereby permitting the clutch-key to couple the driving power to the cam-shaft 59. This causes the hammer-die to deliver one or more sharp and rapidly successive forming or drawing blows upon the burred or upset portion of the chain-link while it is still hot and plastic as a result of the welding heat, as will be more fully explained hereinafter. it will be noted that the precedence of the operation of raising the lower or supporting linishing-die over the operation of starting the opposite die insures the chain-link against being engaged by the latter die before the supporting-die is in position to sustain and react against the impact or pressure. This provision is of course very necessary, since such a premature unsupported action of the die would bend the link out of form, but would not reduce its bur. Immediately after engaging the trip-collar and actuating the clutchcontrolling lever to start the raising-cam 58 the pawl 16, carried still farther forward by the continued downward movement of the finishing-lever, passes beyond position of engagement with the trip-collar and releases the latter, whereupon theretractile tension-spring 57 restores the clutch-controllinglever 63 to its normal position, in which its arm will be engaged by the arm of the clutch-key and stop the rotation of the cam-shaft and its raising cam. Obviously the replacing of the clutchcontrolling lever and elbow-lever 53 to normal position also restores the rock-shaft 4:8

and its trip-collar in the proper angular positions to be again actuated by the pawl in its forward movement. During the return or upward movement of the finishing-lever the lower hammer-die slide 38 is of course depressed with its die-post and die, while the clutch-actuating pall 46 moves backward. During such backward movement of the pawl its pawl-tooth is engaged by the trip-tooth 47 and is placed downward, so as topass underneath the latter, while the pawl-spring 4 L yields and permits the pawl to turn upon its pivot to accommodate the action. Such return movement of the finishing-lever and its connected parts is effected by a long retractive tension-spring 115, stretched between an anchor-pin 138, inserted in the left leg of the frame near its rear edge, and the outer end of a spring-pin 137, inserted radially in the hub of the rocker-arm 35, linked to the finishing lever.

Upon the rear end of the casting 10, constituting the pivotal end of the clamping-lever 9, or otherwise connected with said lover or the primary toggle is the controlling device which governs the actionof the cut-off devices which stop the flow of the heating-eurrent through the work when the workholder has been moved to a prixletermined extent. Such controlling device may be of the character or operate upon the general principle described in prior patents, among which may be cited United States Letters Patent to It. Thomson, No. 385,022, dated June 26, 1888.

For the purpose of exemplifying my present invention 1 have shown said controlling device as an electric circuit closer or breaker, here shown, however, as a circuit-closer comprising a contact-spring l1 and a cooperating contact-pin mounted on a suitable post 13 fixed upon the table, but preferably insulated therefrom. The contact-spring is so mounted upon the parts that when the work-holder is moved in a direction to clamp the work and apply pressure to the same said contact-spring will make contact with the pin, and thereby close a circuit which calls into action the devices for cutting oil the flow of current, as described in patent to Lemp and Anderson, No. 519,336, already referred to. it will be understood, however, that said electrical contact might operate through the intervention of other circuits and devices to cause the How of heating-current to cease when the work-holder has moved to a predetermined extent.

The contact-pin mounted in post 13*1 is adjustable, so as to vary at will the amount of movement of the clannnng-lever and workholder which shall be required to effect the contact. The contact-pin may be secured in any position by means of the set-screw ear, bearing upon it and inserted in the top of the post. These parts constitute an adjustable switch for automatically controlling the welding-current in the chain-link. By a circuit not shown on the drawings the switch is included in series with the current-controlling coil 112 and the actuating-coil of an electromagnetic circuit-breaker controlling the primary circuit which feeds the primary coils 110 and 111 of the transformer. This circuitbreaker and the said primary circuit are also omitted from the drawings, since their arrangement is well known to the art. \Vhen the automatic current controlling switch closes the circuit of the current-controlling 1 cell 112 through the actuating-magnet of the circuit-breaker, the latter opens the primary circuit, and thus stops the flow of the welding-current.

The link and its ends which are to be welded together are so formed, Fig. 18, that the ends touch (or by application of end pressure on the link may be made to touch) at their inner sides 1, while a small gap 1 remains between their outer sides. In Fig. 18 this gap is much exaggerated. It need only be sufficient to prevent conductive contact between the ends at their outer sides. The link is placed, centered, and clamped between the holding-dies a and 5, as before described. If its inner ends do not touch, they may be brought into conductive contact by a slightly-increased pressure on the clamping-lever. The contact-electrodes are then brought forward by a downward pressure on the foot-treadle until they make contact with the side of the link which is to be welded and on either side of the juncture and preferably equidistant therefrom. The'primary circuit is closed, thus inducing a current in the secondary circuit or loop of which the contact-electrodes are the active terminals. The secondary current passes, as indicated by broken lines, fromone contact-electrode to the other through the link and through the inner contact 1. of its contiguous ends. Meanwhile the operator maintains an end pressure of the holding-dies on the link by means of the clamping-lever 9. Since the contact is the greatest resistance in the circuit, the link at this point is rapidly heated by the current until it becomes soft and plastic and yields and spreads under the longitudinal or end pressure to which the abutting surfaces are subjected. As the contact-surfaces thus yield, the operator gradually but quickly brings the holding-dies closer and closer together, thus gradually but quickly bringing more and more surface of the link ends into conductive contact, while the heat gradually but rapidly spreads toward the outer side of the juncture. This operation continued quickly brings into contact, heats, welds, and spreads or upsets the entire cross-section of the abutting link ends, thus completing the welding of the link. The foregoing method of heating is found necessary, because in practice if the abutting link ends touch initially throughout their entire opposing surfaces or at the outer side thereof the heat is developed at the outer side of the contact first, and the inner side thereof cannot be sufficiently heated without concurrently heating the outer side to an excessive and prohibitive degree. This is due to the fact that when the abutting link ends touch throughout their entire adjacent surfaces the circuit of least resistance and inductance from one contact-electrode to the other is through the outer side of the abutting link ends and the outer side of their contact, which side is next the contact-electrodes. As a result the heating-current is concentrated in such outer side. This effect is even greater with the alternating currentgenerally used in electric welding than with a direct current, since at high frequencies the inductive resistance or inductance adds greatly to the total impedance of the circuit through the inner side of the link. If the link to be welded is of iron, the displacement of heat ing-current and heating effect is rendered still greater by the greater inductance of the inside circuit through the magnetic medium and by the fact that the permeability or magnetic susceptibility of the outer side of the abutting link ends and their contacts is greatly reduced by their increase in temperature, thereby still further reducing the inductance of the outer side of the circuit.

As the clamping-lever reaches the position corresponding to the completion of the weld the automatic current controlling switch causes the circuit-breaker to operate and terminates the welding-current, as before explained, the link having assumed the form shown in exaggerated degree in Fig. 19. The outer side I of the link being too cold to be upset by the end pressure of the holding-dies is compelled to bend in order to accommodate the lateral upsetting and concurrent longitudinal contraction of its opposite side. It is obvious that this flexure or bending of the cold side of the link would develop a tension in the welded side which would open the juncture if the end pressure of the dies were relieved while the weld was still hot and soft. It is further obvious that if the link were allowed to cool and were used in this condition the internal stresses developed by the welding strain would still exist and would weaken the link. To avoid both these contingencies, as well as to accomplish the fundamental object of drawing out the upset itself, the following series of operations is enacted.

The end pressure of the holding-dies is maintained by the operator, and the foot-pressure on the treadle is relieved, permitting the contact-electrodes to be retracted. The finishinglever is then pressed downward, raising the lower hammer-die into operative engagement with the upset portion of the chain-link and starting the upper hammer-die, which strikes one or more blows upon the burred or upset portion while it is still hot and soft, thus hammering down the bur and drawing off the upset, restoring the welded side of the link to normal length and diameter, and nicely rounding it in the concave surfaces of the dies. Meanwhile of course the end pressure of the holding-dies may be gradually relieved to accommodate the consequent elongation of the link, which is finished in perfect form, as illustrated in Fig. 20. Obviously by such straightening out of both sides of the link the internal stress before referred to is eliminated.

After welding and drawing the link as set 

